This invention relates to a method for applying elastomeric material to a core, and more particularly, to such a method in which elastomeric material is applied to opposite sides of a toroidal core.
U.S. Pat. No. 3,606,921 issued to Grawey (assigned to the assignee of this application) discloses a novel, oval pneumatic tube-tire. Such tire is generally constructed by forming an oval, toroidal tube member of elastomeric material on a disintegrable core, winding inextensible filament about the toroidal tube member, and applying further layers of material to form the final tube-tire as illustrated therein. The core is then disintegrated and removed from within the tube-tire.
Of particular importance in the manufacture of such tire as disclosed in that patent is the proper formation of the oval, toroidal tube member on the disintegrable core, in preparation for the wrapping of filament material thereabout. Obviously, the method and the apparatus for practicing such method should be as simple and effective as possible, especially considering that the core which is used may be extremely heavy and large.
While the method of forming the tube by means of wrapping tape about the core has proved to be relatively effective, it will be understood that such wrapping is a relatively time-consuming operation, and must be done with extreme care so as to prepare a proper surface for the wrapping of wire thereon. Even if such operation is undertaken with great care, the lap marks which result from the overlapping of such tape material being wrapped are a hindrance to the proper wrapping of the wire thereon, it being evident that the presentation of a smooth tube surface to the wire to be wrapped thereon is preferable.
It will also be understood that in certain applications, an annular strip of elastomeric material is to be applied to each side of the core, actually being applied to elastomeric material already applied to the core, and forming a part of the oval, toroidal tube member. While it is understood that such side-wall portions of the toroidal tube member can also be applied by hand, it will be understood that such hand application is a relatively time-consuming operation, and must be done with extreme care so as to properly position such added elastomeric material.
Of interest in this area are U.S. Pat. No. 3,608,016 to Loberod et al., U.S. Pat. No. 2,953,814 to Mumford, U.S. Pat. No. 1,856,694 to De Correvont, U.S. Pat. No. 3,159,695 to Behringer, U.S. Pat. No. 2,830,818 to Otto, and U.S. Pat. No. 3,342,914 to Edwards. However, it will be seen that none of these patents are concerned with application of elastomeric material to a toroidal core. For purposes of the claims in this case, the term "core" is to be understood to mean not only the actual base core of, for example, sand, but also any elastomeric material which has been deposited on such base core. That is, the core acted upon in the method and by the apparatus of the claims is to be understood to include not only the base core, but also any elastomeric material already applied to such base core at that point in operation.